solve tracer bug: Continous density has negative axis beast-dev/tracer#111
solve tracer bug: Continous density has negative axis beast-dev/tracer#111

beast-dev/beast-mcmc,adamallo/beast-mcmc,adamallo/beast-mcmc,beast-dev/beast-mcmc,adamallo/beast-mcmc,beast-dev/beast-mcmc,adamallo/beast-mcmc,beast-dev/beast-mcmc,beast-dev/beast-mcmc,beast-dev/beast-mcmc,adamallo/beast-mcmc,adamallo/beast-mcmc